Pick-up trucks are widely used in the United States, mainly for transporting or hauling of building materials, goods, and sometimes entertaining vehicles such as boats or all terrain vehicles (ATVs). There are many types of pick-up trucks, ranging from compact trucks to so-called full-size pick-up trucks in terms of dimensions and carrying capacities. In general, it is not easy to load a pickup truck because the goods need to be lifted before being positioned in the cargo area of the truck. When the goods are heavy, it would be almost impossible to lift them without additional equipment.
To facilitate the loading of goods, many kinds of removable or attachable ramps and slopes have been developed. In these designs, generally the ramp will be formed with one end of the ramp being positioned on the edge of the truck cargo area and the other end of the ramp abutting the ground. Then the goods may be pushed or trolleyed on the ramp from ground level to the cargo area of the truck. The following patents may serve as examples for the general ramp designs:
U.S. Pat. No. 5,273,335 discloses a combination ramp and tailgate structure for installation and use in pickup trucks in which the structure would replace a conventional tailgate. The ramp/tailgate structure includes first, second, third and fourth generally rectangular frame member, the first and second of which are slidably coupled together to move between a nested or collapsed position and an extended position, and a third an fourth of which are likewise slidably coupled together to move between a nested or collapsed position and an extended position. The slidable movement between frame members is in the planes thereof so that a low profile, compact configuration may be maintained when in the collapsed position, yet allowing sufficient thickness of the members to permit the ramp to support heavy loads. When the frame members are in nested positions and the when the third frame member is pivoted into a position parallel with the second frame member, the frame members may be pivoted as a unit to an upright position to serve as a conventional tailgate. When the frame members are moved respectively to their extended positions and when the third frame member is pivoted so that all frame members are generally parallel in the same place, with a rearward side or edge of the fourth frame member in contact with the ground, the ramp/tailgate serves as a ramp extending from the ground to the bed of the pickup truck.
U.S. Pat. No. 5,244,335 discloses a telescopic tailgate ramp having a base tray and a series of telescopically-connected trays that are slidable with respect to one another and are stackable to replace a tailgate of a vehicle. Each tray is a plate with end pieces on each side that engage the end pieces of a preceding or succeeding tray. The end pieces have a channel and a tenon-like portion that engage a corresponding tenon or channel portion of a preceding or succeeding tray. Each plate has a corrugated surface for enhancing traction. The trays are prevented from being fully withdrawn from one another due to the placement of pins in corresponding channels and the tenons that engage each other. The trays succeeding the base tray are prevented from sliding past the rear portion of a preceding tray or the rear portion of the base tray securing an obstruction over the rear portion of each channel. The base tray holds the other trays and is pivotable within the tailgate frame of a vehicle upon which it is mounted. The base tray is also pivotable about an axis through points on support bars that are attached to the base tray. Handles facilitate movement and the manipulation of the ramp in general and the individual tray section.
Another problem that is widely encountered by users of pick-up trucks is that the exterior cargo area—the cargo “bed”—is not spacious enough to accommodate the goods that are being transported. In particular, the most likely scenario is that the cargo bed is not long enough—the length of the bed from back of the truck cab to the tailgate is not sufficient—to hold certain articles. For example, one likely use of a pick-up truck is to transport ATVs. However, while the length of the cargo bed for a full-size pick-up truck generally ranges from 90 to 100 inches (229 to 254 cm), a typical ATV usually has a length of about 65-75 inches (165 to 190 cm). Therefore, the cargo bed of a full-size pick-up truck is more than enough for a single ATV, but not enough for two, while the capacity to transport two ATVs may be crucial for the economical planning of sports activities or utility usages with ATVs. Here, the transport of ATV serves only as an example. Enhancing the capacity to carry more goods is desirable without attenuating safety precautions.
To address the issue of carrying capacities, some patents have aimed at providing an extender to the cargo bed of a pickup truck. The following patent is an example of such designs:
U.S. Pat. No. 7,703,825 discloses an extender for a bed of a truck, wherein the extender comprises a frame that has front end, a rear end and side. At least one, and preferably two, spaced apart connector brackets extend outwardly away from the rear end of the frame. The connector brackets are designed to rest upon an end portion of the truck bed when the truck's tailgate has been removed. The connector brackets are preferably bolted into the truck bed, but may be frictionally engaged therewith. A strut extends downwardly from the frame and is connected to a rearward extending longitudinal support. The support is secured to the truck's trailer hitch. The extender is therefore supported by both the connector brackets and the hitch. The length of the strut is vertically adjustable to allow the extender to be secured to any type of truck. The longitudinal support is also slidably adjustable onto the trailer hitch to provide for the extender to be secured to any type of truck. The frame preferably is formed with a pair of spaced-apart wheel wells so as to receive a pair of wheels of a vehicle loaded onto the truck bed. The frame may be provided with a pair of ramps to assist in loading of the truck and with an extended hitch to allow a trailer to be connected to the truck.
In addition, some patents teach structural modifications of the cargo bed and/or the tailgate to a ramp/extender combination. The following patent serves as an example:
U.S. Pat. No. 7,309,202 discloses a system for transporting and storing a portable combination table/ramp device in a truck bed, including a substantially flat platform supported by a plurality of support members positioned between the platform and the truck bed and defining a plurality of elongated recesses therebetween. Elongated table top portion and elongated bench seat portions with tailgate-engaging portions connected thereto are received in the recesses. A plurality of retractable table leg assemblies are connected to the table top portion. A connector is coupled to each respective table leg assembly for connecting the elongated bench seat portion thereto. Each respective table leg assembly is retractable to a storage position substantially adjacent the elongated table top portion and extendable to a deployed position extending between the table top portion and the ground.
While the ramp designs and the extender designs address only part of the problem, the prior art ramp/extender combinations tend to employ complicated structures that are difficult to make and to operate. Not only may the complication add to cost as to manufacturing and implementation, it may also increase the chances of accidents due to the failure of operation. The current invention discloses ramp structures that may serve as extenders for the truck cargo bed. The structure disclosed in the current invention is distinctive and simple and it addresses the problems raised above with a cost-effective design. In conclusion, various implements are known in the art, but their structures are distinctively different from the current invention. Moreover, the prior art fails to address all of the problems solved by the invention described herein. One embodiment of this invention is illustrated in the accompanying drawings and will be described in more detail herein below.